It is considered to record a predetermined data pattern into a predetermined portion of a CD-ROM disc, thereby identifying the disc and preventing a copy-thereof. In the case of recording the predetermined data pattern into the predetermined portion of the disc as mentioned above, it is considered to replace the data in the predetermined portion of the disc with the predetermined data pattern. However, since error correction encoding has been performed in the CD-ROM, if the data in the predetermined portion of the disc is replaced with the predetermined data pattern, a trouble occurs in an error correcting process.
It is, therefore, considered to arrange data corresponding to the predetermined data pattern into the recording data of one block. That is, the data which is recorded into the CD-ROM is modulated from 8 bits to 14 bits by EFM modulation. Merging bits of 3 bits are added to suppress a DC component. It is considered to arrange the corresponding recording data in a manner such that when the data is EFM (8 to 14 Modulation) modulated and DC component suppression bits are added and the resultant data is recorded onto the disc, a predetermined pattern is obtained.
However, the data in the CD-ROM is subjected to an error correction encoding process of a CD-ROM mode 1 and the data is further interleaved by a CIRC (Cross-Interleave Reed-Solomon Code) and error correction encoded. Therefore, the recording data of one block is dispersed and recorded onto the disc. Thus, if the corresponding data is arranged in the recording data of one block so that the predetermined data pattern is recorded into the predetermined portion, the corresponding data is dispersed and arranged into each frame before a CIRC process. Although a method whereby the recording data corresponding to the predetermined data pattern which is recorded into the predetermined portion of the disc is dispersed into each frame of the recording data can be obtained on the basis of the interleave of a CIRC system, a correspondence relation between them is complicated.
Data such as sync, header, all “0”, and the like exists in the data of one block as a recording unit of the CD-ROM. Those data cannot be changed. An error detection code and a parity for error correction cannot be determined before the data is recorded.
When the data corresponding to the predetermined data pattern is dispersed and arranged into the recording data of one block so that the predetermined data pattern is arranged into the predetermined portion on the disc of the CD-ROM, there is a case where the data corresponding to the predetermined data pattern becomes a position of auxiliary data such as sync, header, parity, or the like. Particularly, since the parity exists among a few frames in one block, it is difficult to avoid a situation such that when the corresponding data is dispersed and arranged in the data of one block so that the predetermined data pattern is arranged into the predetermined portion, the corresponding data coincides with the position of the parity. According to such a method, consequently, it is difficult to record the predetermined data pattern into the predetermined portion on the disc without causing a problem in the error correcting process.